Abstract: To provide an image processing system and an image decoding apparatus that can limit compression ratio decrease and image quality deterioration and efficiently reduce an information amount. An image processing system that compresses and transmits an input image signal including pixel values corresponding to respective pixels, including: a dynamic range compression unit configured to compress, by a predetermined coefficient, a dynamic range of each of the pixel values corresponding to a background region other than a region of interest (ROI) designated as a desired region for the pixel values in an image based on the input image signal, to generate a low dynamic range image signal; a coding compression unit configured to compress the low dynamic range image signal in accordance with a predetermined image coding scheme to generate compressed image data; and a bit stream transmitter configured to output a bit stream signal including ROI information, the predetermined coefficient and the compressed image data.

Abstract: To provide an image processing system and an image decoding apparatus that can limit compression ratio decrease and image quality deterioration and efficiently reduce an information amount. An image processing system that compresses and transmits an input image signal including pixel values corresponding to respective pixels, including: a dynamic range compression unit configured to compress, by a predetermined coefficient, a dynamic range of each of the pixel values corresponding to a background region other than a region of interest (ROI) designated as a desired region for the pixel values in an image based on the input image signal, to generate a low dynamic range image signal; a coding compression unit configured to compress the low dynamic range image signal in accordance with a predetermined image coding scheme to generate compressed image data; and a bit stream transmitter configured to output a bit stream signal including ROI information, the predetermined coefficient and the compressed image data.

Abstract: A transmission terminal includes an information generation unit, a transmission unit, a delivery management unit, and a reception unit. The information generation unit generates information that is to be transmitted to a destination reception terminal. The transmission unit transmits information that the information generation unit has generated. The delivery management unit manages transmission of information. The reception unit receives information that the destination reception terminal transmits. Furthermore, the information generation unit generates or receives transmission information that is to be transmitted to the destination reception terminal and generates redundant information for the destination reception terminal to restore the transmission information.

Abstract: An information providing server obtains user information from a user apparatus. The user information is dependent on a place at which the user was previously located. The information providing server decides, from the user information, whether the user has been present within a permission zone including an information acquisition apparatus, and interconnects the user apparatus and the information acquisition apparatus, directly or indirectly, only if such is the case. Users who were present within the permission zone are able to obtain information acquired by the information acquisition apparatus without going through a preliminary registration procedure, while other users are unable to obtain the acquired information.

Abstract: A transmission terminal includes an information generation unit, a transmission unit, a delivery management unit, and a reception unit. The information generation unit generates information that is to be transmitted to a destination reception terminal. The transmission unit transmits information that the information generation unit has generated. The delivery management unit manages transmission of information. The reception unit receives information that the destination reception terminal transmits. Furthermore, the information generation unit generates or receives transmission information that is to be transmitted to the destination reception terminal and generates redundant information for the destination reception terminal to restore the transmission information.

Abstract: A transmission header compressor and a moving-picture encoder each include a respective circuit for synchronizing a timing at which the compressor inhibits compression of transmission headers with a timing at which the encoder executes intra-frame coding. A moving-picture transmission system including the compressor and encoder is also disclosed.

Abstract: In a picture transmission system that transmits a series of pictures from a coding apparatus to a decoding apparatus, each picture being coded and decoded with reference to a preceding picture, when a transmission error occurs, the decoding apparatus detects a decoding error caused by the transmission error and sends an error signal to the coding apparatus. The coding apparatus and decoding apparatus then both modify part of a reference picture affected by the decoding error, making identical modifications. A subsequent picture is coded and decoded with reference to the modified reference picture, thereby recovering from the transmission error with minimum loss of coding efficiency and picture quality.

Abstract: When a segment of a compressively coded stream of moving-picture data is rendered unusable by an error, usable decoded data are discarded in a range adjacent to the unusable segment, to avoid picture defects that might result from the use of incorrectly decoded data. The discarding range may extend from one end or from both ends of the unusable segment. When the data are coded in two or more different modes, two or more corresponding ranges of different lengths may be set.

Abstract: A picture decoding apparatus decodes a series of coded frames, each including a temporal reference. Past temporal references are used to estimate the temporal reference of the-current frame. If the temporal reference differs greatly from the estimated value, it is modified according to the estimated value. A coded frame may be divided into segments, each segment having its own temporal reference. In this case, the temporal references received in one coded frame are stored and compared, and a single temporal reference is selected for the coded frame. As a result, temporal-reference errors do not seriously disrupt the timing of the decoded picture.

Abstract: A moving picture coded by inter-frame coding, with motion compensation, is decoded by an apparatus that stores at least two previously decoded frames, together with information identifying any erroneous parts of the previously decoded frames. The current frame is decoded with reference to a predicted frame assembled from decodable parts of the previous frames. When a motion vector points to a non-decodable part of a previous frame, it is extended farther back to a decodable part of an earlier frame. The extension can be made linearly, or by using previous motion vectors. Picture distortion caused by error propagation is thereby reduced.

Abstract: A transmission system transmits a series of coded frames from a transmitting device to a receiving device, using both intra-frame coding and inter-frame coding. The receiving device decodes the frames and sends acknowledgment signals to the transmitting device. The transmitting device selects the reference frame employed in inter-frame coding according to these acknowledgment signals. The method of reference frame selection can be varied according to an assessment of transmission channel quality. The assessment criteria, or the reference frame selection method itself, can be varied in response to input from a human user.

Abstract: Each of consecutively transmitted frames representing motion images is composed of a given number of blocks. A SAD cumulative value representing an image variation history is derived per block. Blocks to be refreshed, i.e. to be intraframe-coded, are selected based on the SAD cumulative values. Specifically, a given number of the blocks whose corresponding SAD cumulative values are larger among all the SAD cumulative values are selected, or those blocks whose corresponding SAD cumulative values are greater than a threshold value are selected. Thus, the blocks which actually require “refresh” can be preferentially refreshed.

Abstract: Each of consecutively transmitted frames representing motion images is composed of a given number of blocks. A SAD cumulative value representing an image variation history is derived per block. Blocks to be refreshed, i.e. to be intraframe-coded, are selected based on the SAD cumulative values. Specifically, a given number of the blocks whose corresponding SAD cumulative values are larger among all the SAD cumulative values are selected, or those blocks whose corresponding SAD cumulative values are greater than a threshold value are selected. Thus, the blocks which actually require “refresh” can be preferentially refreshed.

Abstract: A transmission header compressor and a moving-picture encoder each include a respective circuit for synchronizing a timing at which the compressor inhibits compression of transmission headers with a timing at which the encoder executes intra-frame coding. A moving-picture transmission system including the compressor and encoder is also disclosed.

Abstract: A coder receives from a decoder the reception result of coded data, estimates the reception capability of the decoder and, based on the estimate result, updates accordingly the reference data on which prediction coding is to be based. This enables the reference data to be updated according to the reception capability of each decoder.

Abstract: A data reception unit having improved robustness against synchronization code errors. In data transmission, the synchronization code is always located in the headers of coded data contained in the package payload. Where the number of synchronization code bit errors falls below a threshold value, decoding is performed ignoring the errors. Where the number of bit errors exceeds the threshold value, the encoded data in the packet is discarded. Robustness against errors are modified through manipulation of the threshold value in response to transmission path type and error status.

Abstract: A transmission system transmits a series of coded frames from a transmitting device to a receiving device, using both intra-frame coding and inter-frame coding. The receiving device decodes the frames and sends acknowledgment signals to the transmitting device. The transmitting device selects the reference frame employed in inter-frame coding according to these acknowledgment signals. The method of reference frame selection can be varied according to an assessment of transmission channel quality. The assessment criteria, or the reference frame selection method itself, can be varied in response to input from a human user.

Abstract: A picture coder and a picture coding method which quickly recover the degraded picture quality of partitions, which could not be decoded due to a data error or a data loss, without increasing the amount of coding. A picture coding method or a picture coder is operable for coding picture data of a frame which is divided into a plurality of partitions, each partition being coded in a temporal correlation coding method or in an intra-picture coding method, wherein one or more partitions are determined to be refreshed for each frame or for each plurality of frames and wherein partitions determined to be refreshed are coded in the intra-picture coding method. A temporal change amount for each partition is calculated and, based on the temporal change amount for each partition, one or more partitions are determined to be refreshed.

Abstract: A picture decoder decodes P frames without having to wait for a next I frame even if a data loss occurs, and ensures quick recovery from degraded picture quality. The picture decoder sends decoding status information on received coded data to a coder. This makes it possible for the picture coder to perform coding using a frame, successfully decoded by the decoder, as a reference frame. Also, the picture decoder according to the present invention saves in frame memory a frame that is likely to be used as the reference frame, decreasing a probability that received coded data cannot be decoded because there is no reference picture in frame memory and thus increasing coding efficiency. This also keeps the reference frame memory size of the picture decoder to a minimum.

Abstract: In a system that uses inter-frame coding to compress blocks of data for transmission from a transmitting device to a receiving device, and sends acknowledgment signal back from the receiving device to the transmitting device, the receiving device packs decoding-error information about multiple blocks into each acknowledgment signal. The transmitting device unpacks the acknowledgment signal to obtain the decoding-error information, and uses this information to keep from performing inter-frame coding with reference to data that the receiving device was unable to decode. The bandwidth saved by packing information about multiple blocks into each acknowledgment signal can be used to enhance reliability by repeating the information in multiple acknowledgment signals.